If they have used the wrong socket what makes you think they haved wired up correctly
Looking from the rear of the socket
(the terminal screwside)
top pin .earth .white wire
Next row down left pin black wire lhd side lights
……………rhd pin brown wire rhd side lights
2nd row lhd pin yellow .lhd indicater 2 row mid pin not used 2nd row rhd pin green wire .rhd indicater
Botton row middle red wire .stop lights
But not matter std 12v trailer socket totaly different socket and wire locations